. The Earth beneath the sea : History. Ocean bottom; Marine geophysics. SECT. 3] TURBIDITY CURRENTS 745 full-scale experiment in erosion, transportation, and deposition of marine sediments by a turbidity current in which the submarine telegraph cables served to measure its progress and to give tangible evidence of its force". Following this earthquake, which shook the continental slope south of New- foundland, all the submarine telegraph cables lying downslope (south) of the epicentral area were broken in sequence from north to south (Fig. 1). According to Heezen and Ewing's explanation e
. The Earth beneath the sea : History. Ocean bottom; Marine geophysics. SECT. 3] TURBIDITY CURRENTS 745 full-scale experiment in erosion, transportation, and deposition of marine sediments by a turbidity current in which the submarine telegraph cables served to measure its progress and to give tangible evidence of its force". Following this earthquake, which shook the continental slope south of New- foundland, all the submarine telegraph cables lying downslope (south) of the epicentral area were broken in sequence from north to south (Fig. 1). According to Heezen and Ewing's explanation each successive cable was broken by a turbidity current which had originated as a series of slumps in the epicentral. 50 100 150 200 250 300 Distance from (00:59) break measured along deepest portion of bight 350 Fig. 3. Time-distance graph of the 1929 Grand Banks turbidity current. (After Heezen and Ewing, 1952.) _ /^--:i area. The current travelled down and across the continental slope, continental rise and ocean basin floor, and, continuing far out onto the abyssal plain, reached a limit well over 450 miles from its source area on the continental slope (Fig. 2). On the continental slope where the bottom gradient is 1:10 to 1:30 the velocity of the current exceeded 50 knots; and out on the abyssal plain where the gradient is less than 1: 1500 its velocity, although diminished, still exceeded 12 knots (Fig. 3). Subsequent exploration of the area with the piston corer revealed a one-meter thick, uppermost bed of graded silt containing shallow- water microfossils (Heezen, Ericson and Ewing, 1954) overlaying abyssal lutite. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hill, M. N. (Maurice Neville), 1919-. New York : Interscience Pub.
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